DP8422ATVX-25

The DP8422ATVX-25 from Texas Instruments is a microCMOS programmable controller designed to interface between dynamic RAM and 8-, 16-, and 32-bit systems. It generates all necessary access control signal timing for DRAMs and includes an on-chip refresh request clock for automatic DRAM array refreshing. Refreshes and accesses are arbitrated on-chip.

Key features include a high-precision delay line for critical DRAM access timing, microCMOS process for low power consumption, and high capacitance drivers for RAS, CAS, WE, and DRAM address signals. The device supports nibble, page, and static column DRAMs, and includes byte enable signals for byte writing in word sizes up to 32 bits without external logic. It operates at speeds of 25 MHz and features on-board arbitration logic for Port A, Port B, and refresh.

This controller is suitable for systems requiring direct interface to major microprocessors. It provides 4 RAS and 4 CAS drivers, with programmable configuration. The DP8422A variant specifically offers two access ports (A and B) to simplify dual accessing, with arbitration handled on-chip. The device is available in an 84-PLCC package and operates within a temperature range of 0°C to 70°C, with a voltage range of 4.5V to 5.5V.